Wow, suprised to hear all the nagative comments about black plastic edging. Ive been in business for six years, and worked for a landscaper for 5 years before that, and I can only remember repairing about a 6foot section that came up. I put it in with a Brown trencher, with an edging blade, and use Valley V iew Ace of diamond edging. I do use more stakes (usually 5 to 6 depending on how many curves), but to this day, have had basically no problem with it. I bout the edger mid way through my first landscaing job. I had put in about 120' of edging by hand, i wan to say it took us about 2 hours to put it in. I went and bought the edger, and put in the other 100 feet in about 25 minutes. I highly recomend it, its paid for itself over and over.

Why are you using the bed edger with the 4" trenching blade?
You need to use the straight edge blade on the trencher. This allows the black plastic to go straight in, tight, and no holding it for back fill. But I'm in aggreement with all of you T-A-C-K-Y!!!
And I'll never do it...for anyone!!!!!